Adaptation to life on land was among the most important events in vertebrate evolutionary history. During the late Devonian, approximately 350 million years ago, fish left the water and colonised the land. Up until now, this extraordinary transition has been inferred from the fossil record. Yet, fossil evidence is fragmentary, mostly morphological and consequently limits the inference of adaptation. In particular, fossils cannot identify the genetic changes, ecological shifts or behaviours that underlie adaptation. There are however, a number of contemporary examples of fish that have made or are making a similar transition to life on land. Within the family Blenniidae there are fish from small islands throughout the Indian and Pacific Oceans that essentially represent each evolutionary step involved in the transition to land. Within this remarkable system, there are genera that are almost exclusively terrestrial, spending the vast majority of their time out of water. That is, they do not voluntarily return to water. Sister to these “land fish” are genera that are amphibious, spending part of their time on land and part of their time in the water. Ancestral to all of these are a variety of genera that retain their aquatic phenotype. Collectively, these fish provide a unique and unrivaled opportunity to investigate the genetics and behaviour of a land invasion from aquatic origins in vertebrates. Here using a combination of phylogenetics, ancestral character state reconstructions and field based behavioural observations of these fish I will explore the answers to the following questions: 1. what drive fish to make a transition to land and 2. is the invasion of land by fish and unusual or frequent evolutionary event? These results will help reveal the ecological, behavioural and evolutionary processes that might have been involved with the initial invasion of land by fish in the Devonian.